Bahr B A, Parsons S M
J Neurochem. 1986 Apr;46(4):1214-8. doi: 10.1111/j.1471-4159.1986.tb00640.x.
Steady-state initial velocity uptake of [3H]acetylcholine ([3H]ACh) by purified Torpedo electric organ synaptic vesicles was studied. Transport specific activity decreased at higher vesicle concentration. Michaelis-Menten type kinetics describe [3H]ACh active transport at constant vesicle concentration with no evidence of cooperativity or transporter heterogeneity. The ACh dissociation constant is about 0.3 mM, transport has a maximal velocity of about 1.6 nmol/min/mg protein, and both are dependent on the vesicle preparation. Nonradioactive ACh was a competitive inhibitor with respect to [3H]ACh. The potent transport inhibitor dl-trans-2-(4-phenylpiperidino)cyclohexanol (AH5183) is a non-competitive inhibitor with respect to [3H]ACh, with an inhibition constant of 41 +/- 7 nM. Inhibition by AH5183 is reversible. The results suggest that AH5183 does not bind to the ACh transporter recognition site on the outside of the vesicle membrane, and thus it might inhibit allosterically.
研究了纯化的电鳐电器官突触小泡对[3H]乙酰胆碱（[3H]ACh）的稳态初始摄取速率。在较高的小泡浓度下，转运比活性降低。米氏动力学描述了在恒定小泡浓度下[3H]ACh的主动转运，没有协同性或转运体异质性的证据。ACh解离常数约为0.3 mM，转运的最大速度约为1.6 nmol/分钟/毫克蛋白质，两者均取决于小泡制剂。非放射性ACh是[3H]ACh的竞争性抑制剂。强效转运抑制剂dl-反式-2-（4-苯基哌啶基）环己醇（AH5183）是[3H]ACh的非竞争性抑制剂，抑制常数为41±7 nM。AH5183的抑制作用是可逆的。结果表明，AH5183不与小泡膜外的ACh转运体识别位点结合，因此可能通过变构作用抑制。
